Catheters have become widely used in modern medicine to provide one or more lumens into a patient's body through which a wide variety of procedures may be performed or fluids may be introduced or removed from the patient. Examples include catheters lumens through which minimally-invasive surgical procedures, such as angioplasty balloon deployment or tissue resection, may be performed, catheters for introducing therapeutic substances at desired sites within the patient, catheters for the removal and/or replacement of fluids, such has blood removal and replacement during hemodialysis, and catheters associated with activation of mechanisms for medical devices, such as activation of control cables or application of pneumatic pressure to inflate balloons or expand stents at target locations within the patient.
Inherent with the use of medical devices placed within a patient is the risk of infection from the medical device. While great strides have been made in the last century in preventing infection during surgical procedures, this risk has not been entirely eliminated. For example, it has been estimated that central venous catheters account for more than 90 percent of all nosocomial catheter-related blood stream infections.
In the case of central venous catheters, characteristically, at an infected site a large number of microorganisms are adherent on the catheter, where there is an interaction between the pathogen and the catheter microsurface. Once so infected, the microorganisms adhere to the catheter and rapidly become encased in a polysaccharide matrix or biofilm which protects the microorganisms from the natural defenses of the host. While there have been recent developments of central venous catheters to attempt to reduce the incidence of nosocomial catheter-based infections, such as the use of catheters with liquid chlorohexidine and silver sulfadiazine, or with a combination of minocycline and rifampin, such infections have yet to be eliminated.
The use of antimicrobial agent-bearing intervention devices has been proposed for the management of nosocomial blood stream infections. Antimicrobial agents such as povidone-iodine, chlorhexidine, polymicrobial gel, isopropyl alcohol and hydrogen peroxide have long been used in medical practice as disinfectants, with iodine having been discovered to be one of the most effective antiseptics in the 1870s. Recently, iodine-bearing formulations have been developed that may be applied to, or incorporated into, medical devices to provide controlled in-situ release of iodine as an antimicrobial agent. One potential application of such formulations is an iodine-bearing polymeric rod that can be inserted into a catheter, where the rod delivers iodine to the catheter in order to manage catheter-based nosocomial bloodstream infections. In this example, an iodine-bearing polymeric intervention device is placed within an indwelling catheter. As a result, elemental iodine may be released to diffuse to the catheter wall, and if the catheter wall material is semi-permeable, to diffuse through the catheter wall to the exterior surface of the catheter. Thus, the iodine may be made available to eliminate micro-organisms on both the inner and outer micro-surfaces of the catheter.
Notwithstanding the advantages in catheter-based nosocomial blood stream infection management offered by the use of an iodine-bearing polymeric intervention device, installation or delivery of the device into the catheter presents a number of challenges. For example, during insertion into the catheter, it is highly desirable for the intervention device to remain sterile and, therefore, out of direct contact with equipment, hands, and any other non-sterile surfaces. In addition, due to the relatively low column strength of rod implementations of the intervention devices, control over the rod can be less than desired. There is therefore a need for a delivery system that provides sterility by reducing direct handling of antimicrobial agent-bearing intervention devices. There is also a need for a delivery system that enhances control over the insertion of the intervention device during insertion into the catheter lumen.